The present invention relates to the medical arts, and, more particularly, to monitoring and diagnosis of infections and the like.
Total joint replacement is a surgical procedure to remedy skeletal or cartilaginous injuries that severely limit daily life. Joint replacement surgeries are relatively common.
Bacterial infection of the synovial cavity is a relatively uncommon but dangerous post-surgical complication of total joint replacement. Such infections are difficult to effectively treat because blood does not typically permeate the synovial cavity, which makes it difficult to deliver antibiotics to kill the unwelcome bacteria. Accordingly, early stage detection of synovial infections can improve a patient's outcome, when antibiotics can be orally or intravenously administered while the bacteria count is low. Currently, synovial infections are diagnosed by aspirating the synovial cavity using a syringe. The aspirated fluid then is sent out to a laboratory for analysis.
Various medical conditions, such as infections, chronic diseases, or acute illnesses, produce biomarkers that permeate a person's blood and interstitial fluid. For example, biomarkers may include (by way of non-limiting examples) temperature; sugars such as glucose; ions such as sodium, potassium, chloride, calcium, magnesium, bicarbonate, and/or hydronium (pH); gases such as carbon dioxide, oxygen, nitrogen, or carbon monoxide; metabolites such as urea, creatinine, taurine, or acetaldehyde; proteins such as IL-6 (Interleukin 6), C-reactive protein or clotting factors; and cell count from white blood cells and erythrocytes.
Blood and interstitial fluid can be sampled by minimally invasive techniques, for example, using microneedles to penetrate into or beneath the skin without puncturing venous or muscular tissue. Sampled fluid can be analyzed onboard a sampling device, and simple diagnoses (e.g., an indication of high biomarker level or a direction to take a dose of medication) can be generated by the sampling device based on the analysis of the sampled fluid.